Carburetor



Jan. 6, 1942. J. LICHTENsTElN 2,269,275

` K CRRBURETOR Original Filed F`eb. 5, 1956 INVENTOR.' JoHH/v Z/cHrE/Jrf/N BY d' Patented Jangjs, 1942 CARBURETOR Johan Lichtenstein, Levallois-Perret, France, as-

signor to Societe Generale des Carburateurs y Zenith, Geneva, Switzerland, a corporation of A Switzerland Original application February 5, 1936, Serial No. 62,499.' Divided and this application January 5, 1940, Serial No; 312,613. In Belgium February 8, 1935 3 Claims.

I have appliedfor patent in: Belgium, February 8, 1935, now issued as BelgianPatent No. 407,771; Germany, application Afor patent of addition filed on February 8,1936; Great Britain, February 10, 1936, now issued as British Patent of Addition 474,975; France, February 7, 1936, now issued as French Patent 804,028; Italy, February 3, 1936, now issued as Italian Patent 339,760; Poland, application for patent of addition filed on February 5, 1936; and Czechoslovakia, application for patent of addition filed on February 4, 1936.

This invention rela-tes to improvements in carburetors for 'internal combustion motors, of the type described in Belgian'Patent 406,646, of December 5, 1934, in the name of SocieteGenerale des Carburateurs Zenith, for Improvements in carburetors." The present application is a di,- vision of my copending application, Serial No. 62,499, filed 'February 5, 1936. Y

In said Belgian patent, there is described a carburetor comprising a mixture passage having an air inlet and a mixture outlet connected to the motor,` a throttle controlling the effective cross section of said passage, and a fuel outlet discharging into said passage posterior to the throttle. The carburetor is characterized essentially by a movable control member which controls the pressure at which liquid fuel is supplied to the fuel nozzle, the Aposition of said control member being a function of the absolute pressure obtaining in the mixing chamber of the carburetor posterior to the throttle and preferably of ther absolute pressure which obtains in -said mixture passage lin the vicinity of the fuel nozzle. This control member will be referred to hereinafter as the manometric control member" to facilitate the description. In the preferred embodiment, a second regulating device influencing the discharge of fuel delivered by the i'uel nozale is controlled by the throttle. The manometric control member is arranged in such manner as to provide automatic functioning of the carburetor; that is to say, in such manner that the carburetor will deliver tothe motor a mixture of the correct composition under all conditions of operation, and, when applied to an aircraft carburetor, is furthermore arranged in such manner as to provide an altimetric correction.` that is to say in such manner as to modify the discharge of fuel in the degree required by variations in altitude. y

It is known that the composition of the combustible mixture supplied to' an internal combustion engine need not be an absolutely fixed (ci. gsi-ss) specific consumption. In generaL/this modiilcation of the richness Yis made at the will of the pilot.

The present invention has for its object an arrangement) permitting the richness of thecombustible `mixture to be varied in carburetors of the type described in said' Belgian patent.

According to the present invention, the in- Vfluence of the manometric. control member on the discharge of fuel may be variedrby a supplemental adjusting member. This adjusting member will generally be manually controlled,

Y butit will obviously be possible to control it autothe following description taken in connection l of lever 5 and rod 6.

matically the same as other organs of the carburetor. Many 'ways of realizing the invention will be apparent tothose skilled in the art from with the appended drawing in which:

Figure l is a diagrammatic view showing one form of the invention; and

AFigure -2 is a diagrammatic View showing a modified form of the invention.-

The carburetor shown inFigure l comprises a mixture passage l having an air inlet l and aA mixture outlet 3 connected to the motor. Ther effective cross section of the mixture passage I is controlled by a throttle 4 actuated by n i The fuel nozzlel 'l discharges into venturi l posterior to the throttle l. The cross section of the fuel jet is controlled by a tapered needle!! the-shank 26 ofwhich passes through a bushing y 21 carried by the body of the carburetor. Needle 25-26 is controlled by the throttleA I through the intermediary of .the'arm 2l of lever i, link l! and lever 3D turning aboutthe axis Il.'

The fuel nozzle '.1 is supplied withliquid fuel' 11'.' In the chamber, 'ometric bellows .22 of (the'- length of which lthe Vpressure v `which itis exposed One end |22 of capsule 22 is as corresponding to lean or Obviously, the expressions within the fuel `chamber I3 or any decrease in pressure within the adjoining chamber i5 tends to move membrane l2 upwardly and close the valve I3, I4.

The membrane |2 separates thel fuel chamber I0 from a depression chamber il, which corn municates with the air inlet 2 located at the entrance of the carburetor through a calibrated orifice IB and a conduit i1. Orice l0 could equally well be open directly to the atmosphere.- Chamber i0 communicates also with a chamber i3 through a calibrated orifice i0. Chamber i8 communicates freel with the venturi through a conduit 20. The conduit 2l opens into the ven- 3 at 2|"'in the vicinity vof the fuel Vnozzle 1, that is to say' at' a point in the venturi where the pressure is nozzle 1. The pressure which obtains .in-'the chamber i3 is therefore .approximatelythe same as the pressure whichobtains at the fuel nozzle i3 is disposed a closed man-' the aneroid..,capsule type. varies inaccordance with obtaining in thechamber i3, to

extends through a bushiixed toa rod |23 which the chamber ing v|24 mounted in the top |20 of contact |28 and |23 terminates in a plate |20 which ing about an axis |42.

|22 of capsule 22 is fixed to the end |32 of the chamber i0, whereas its other end |3| is`c`onnected to the end |33 of lever |34. The lever- |24 is connected at a point |35 to a rod |36 which passes through a bushing |21 mounted at the end |32 of the chamber l0, plate |38. The spring |39 presses the plate |20 against the cam |40 carried by a lever' Finally, the lever connected at |43 to a tapered needle |44 which controls the effective cross section of the orifice tion of the orifice of the mixture is modied in the same manner as i9 as a function of the elongation of the capsule 22. similar tothe member 23 of the carburetor shown in Figure i. If the lever |4| is moved to the position shown in broken lines, the cross sec- I3 is enlarged and the richness through the' movement .of the lever |20 in the deactuated by lever |33. Cam constitutes that which has been referred to as the supplementaladjustingimember. The other end |3l of the capsule carries a tapered valve member 23 which controls the vorice I8.

For any given position oflever |30, capsule 22 is more extended the lower the absolute pressure in th'e chamber l0, and consequently, in the venturi B: consequently the cross section of orice I! is greater the lower the pressure in the venturi 0. The depression transmitted to chamber I5 increases as the pressure in the venturi 0 decreases. The pressure in the fuel chamber |0 follows the same fluctuations as the pressure in the chamber i5, so that the discharge of fuel delivered through the fuel nozzle i is smaller the more orice i9 is opened. The shapes of the tapered valve member 23 and the needle 25 are so predetermined that the richness of the mixture delivered by the carburetor varies as a function of the opening of the throttle. Following the usual practice, the regulation is' such that the mixture will have a uniform composition for' all intermediate openings of the throttle, and will be richer for small and for great openings.

When the lever is in the position shown in full lines in Figure l the opening at orifice i9 will be relatively small and the mixture delivered may 'ne considered as that corresponding to nor' mal'operation. If lever |30 is brought to the position represented in dotted lines in Figure l, the capsule is lowered; the effective cross section of 4passage |9 is enlarged, whatever the throttle opening may be; the discharge of fuel is diminished, and the mixture is made leaner. This second position of the lever |30 may be considered economical operation. normal mixture and lean mixture have here only a relative significanoe; they simply mean that in one case the mixture contains a proportion of fuel greater than that iii-the other case, without signifying the absolute value of vthe ratio of the quantity of fuel to the quantity of air in the mixture.

In the arrangement shown in Figure 2, the end displacement -w 3" Although the thereof, it is not limited to auch embodied in other forms within the scopeofthe,

vice shown in Figure 1.

vIn the arrangement shown in Figure 2, the

' same as in the arrangement shown in Figure l.

movement of the supplemental adjusting member is added to the elongation of the capsule to cause of the manometric control member (tapered valve member 23, Figure 1; or 144, Figure 2). One can readily conceive of various other arrangements equivalent to those shown in Figurea 1 and 2, without making it 'necessary to multiply-examples.

invention has been l.described with particular reference to specific embodiments nemend-may be appended claims. y

I claim:

1. In a carburetor having an induction passage, a throttle controlling the passage. a fuel nozzle discharging into said induction passage, a fuel chamber supplying fuel to said nozzle vand having an inlet, a. valve inthe inlet, a suction chamber,

- diaphragm means forming movable walls of said chambers and operatively connected to said valve, and means for varying the suction in said suction chamber to thereby vary the pressure in the fuel chamber comprising conduits connecting the suction chamber with the induction passage respectively anterior and posterior to the throttle, and means including a manometric capsule responsive to variations in the pressure in the induction passage for automatically varying the relative effective cross sections of said conduits:

l in combination therewith of an independently operable manual means for further varying the relative eifective cross sections of said conduits comprising a spring urging the capsule as a unit in one direction, and a pivotally mounted cam having a control lever connected thereto and operable at the will of the operator from a point remote from the engine during substantially nil operating conditions for moving said capsule as a unit in opposition to said spring.

2. A charge forming device for an internal combustion engine comprising an air supply passag e,a throttle therein,a fuel conduit discharging in said passage posterior to the thottle, a throttle controlled variable restriction in said conduit, a fuel chamber supplying fuel to said conduit and having an inlet, a movable wall in said fuel chamber, a valve in the inlet connected to said wall, a variable pressure air chamber having a movable wall connected to said valve, a. suction conduit and an air conduit connecting the air chamber with the air passage respectively posterior and anterior to the throttle, a valve for controlling the relatively effective areas of said suction and air and terminates in a tions from a point remote from the engine 'for varying the position of the valve for a given condition of expansion of the expansible member, said manual means comprising a cam having an operating lever adapted for remote control and means interconnecting th'e cam and valve whereby movement of the cam varies the position of the valve.

3. A charge forming device for an internal combustion engine, including an air supply passage, a throttle therein, a fuel chamber, a variable pressure air chamber, diaphragm means forming movable walls of said chambers, means for discharging the fuel from the fuel chamber into the passage, valve means operatively connected to said diaphragm means for controlling the admission of fuel to the fuel'chamber, conduits connecting the air chamber respectively to regions of relatively low and high pressures in the air supply passage, and means for varying the pressure in the air chamber to thereby vary the pressure in the fuel chamber comprising a valve for controlling the relative effective cross sectional areas pf said conduits, a manometric cap-v sule for varying the position' of said valve in response toA variations in pressure in the air passage posterior to the throttleand a manual control operable at the will of the pilot from a point remote from the device and Without corre- 

